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/*
* Copyright (C) 2016 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "tcp.h"
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
namespace tcp {
static constexpr int kProtocolVersion = 1;
static constexpr size_t kHandshakeLength = 4;
static constexpr int kHandshakeTimeoutMs = 2000;
// Extract the big-endian 8-byte message length into a 64-bit number.
static uint64_t ExtractMessageLength(const void* buffer) {
uint64_t ret = 0;
for (int i = 0; i < 8; ++i) {
ret |= uint64_t{reinterpret_cast<const uint8_t*>(buffer)[i]} << (56 - i * 8);
}
return ret;
}
// Encode the 64-bit number into a big-endian 8-byte message length.
static void EncodeMessageLength(uint64_t length, void* buffer) {
for (int i = 0; i < 8; ++i) {
reinterpret_cast<uint8_t*>(buffer)[i] = length >> (56 - i * 8);
}
}
class TcpTransport : public Transport {
public:
// Factory function so we can return nullptr if initialization fails.
static std::unique_ptr<TcpTransport> NewTransport(std::unique_ptr<Socket> socket,
std::string* error);
~TcpTransport() override = default;
ssize_t Read(void* data, size_t length) override;
ssize_t Write(const void* data, size_t length) override;
int Close() override;
private:
explicit TcpTransport(std::unique_ptr<Socket> sock) : socket_(std::move(sock)) {}
// Connects to the device and performs the initial handshake. Returns false and fills |error|
// on failure.
bool InitializeProtocol(std::string* error);
std::unique_ptr<Socket> socket_;
uint64_t message_bytes_left_ = 0;
DISALLOW_COPY_AND_ASSIGN(TcpTransport);
};
std::unique_ptr<TcpTransport> TcpTransport::NewTransport(std::unique_ptr<Socket> socket,
std::string* error) {
std::unique_ptr<TcpTransport> transport(new TcpTransport(std::move(socket)));
if (!transport->InitializeProtocol(error)) {
return nullptr;
}
return transport;
}
// These error strings are checked in tcp_test.cpp and should be kept in sync.
bool TcpTransport::InitializeProtocol(std::string* error) {
std::string handshake_message(android::base::StringPrintf("FB%02d", kProtocolVersion));
if (!socket_->Send(handshake_message.c_str(), kHandshakeLength)) {
*error = android::base::StringPrintf("Failed to send initialization message (%s)",
Socket::GetErrorMessage().c_str());
return false;
}
char buffer[kHandshakeLength + 1];
buffer[kHandshakeLength] = '\0';
if (socket_->ReceiveAll(buffer, kHandshakeLength, kHandshakeTimeoutMs) != kHandshakeLength) {
*error = android::base::StringPrintf(
"No initialization message received (%s). Target may not support TCP fastboot",
Socket::GetErrorMessage().c_str());
return false;
}
if (memcmp(buffer, "FB", 2) != 0) {
*error = "Unrecognized initialization message. Target may not support TCP fastboot";
return false;
}
int version = 0;
if (!android::base::ParseInt(buffer + 2, &version) || version < kProtocolVersion) {
*error = android::base::StringPrintf("Unknown TCP protocol version %s (host version %02d)",
buffer + 2, kProtocolVersion);
return false;
}
error->clear();
return true;
}
ssize_t TcpTransport::Read(void* data, size_t length) {
if (socket_ == nullptr) {
return -1;
}
// Unless we're mid-message, read the next 8-byte message length.
if (message_bytes_left_ == 0) {
char buffer[8];
if (socket_->ReceiveAll(buffer, 8, 0) != 8) {
Close();
return -1;
}
message_bytes_left_ = ExtractMessageLength(buffer);
}
// Now read the message (up to |length| bytes).
if (length > message_bytes_left_) {
length = message_bytes_left_;
}
ssize_t bytes_read = socket_->ReceiveAll(data, length, 0);
if (bytes_read == -1) {
Close();
} else {
message_bytes_left_ -= bytes_read;
}
return bytes_read;
}
ssize_t TcpTransport::Write(const void* data, size_t length) {
if (socket_ == nullptr) {
return -1;
}
// Use multi-buffer writes for better performance.
char header[8];
EncodeMessageLength(length, header);
if (!socket_->Send(std::vector<cutils_socket_buffer_t>{{header, 8}, {data, length}})) {
Close();
return -1;
}
return length;
}
int TcpTransport::Close() {
if (socket_ == nullptr) {
return 0;
}
int result = socket_->Close();
socket_.reset();
return result;
}
std::unique_ptr<Transport> Connect(const std::string& hostname, int port, std::string* error) {
return internal::Connect(Socket::NewClient(Socket::Protocol::kTcp, hostname, port, error),
error);
}
namespace internal {
std::unique_ptr<Transport> Connect(std::unique_ptr<Socket> sock, std::string* error) {
if (sock == nullptr) {
// If Socket creation failed |error| is already set.
return nullptr;
}
return TcpTransport::NewTransport(std::move(sock), error);
}
} // namespace internal
} // namespace tcp
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